This project examines the physiological effects and the underlying biochemical mechanisms of the action of the delta opioid peptides and a related protein factor HIT (Hibernation Induction Trigger) in organ preservation and protection. HIT (Hibernation Induction Trigger), a partially purified protein factor from winter hibernating woodchucks were compared for compositional and concentration differences with a equivalent protein preparation from summer-active animals. A 88 KDa protein specific to the HIT was thus identified and purified by FPLC and SDS/PAGE. After Western blotting, the purified protein was subjected to proteolytic cleavage. The sequences of the tryptic fragments indicated that the protein does not belong to any known proteins but represents a new hibernation-specific protein.